When to Plant Sunflowers in Flossmoor, IL

One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can figure out when it's possible to plant sunflowers in Flossmoor by using the USDA zone info.


Planting Calendar for Sunflowers

Frost tolerance for sunflowers: Not tolerant of frost.
When to plant: After the last frost.

It's not a good idea to plant sunflowers until after the last frost when the weather gets warmer because they are not cold tolerant.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant sunflowers
Possibly ok, but a risky time to plant sunflowers
Probably not a good time to plant sunflowers

The earliest that you can plant sunflowers in Flossmoor is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant sunflowers and expect a good harvest is probably August. Any later than that and your sunflowers may not have a chance to grow to maturity. If you are starting your sunflowers indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Flossmoor the average date of last frost happens on April 15. You can expect an average low temperature of -15°F in the coldest months of winter.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Flossmoor and it is different every year. Half of the time in Flossmoor it frosts late in the year after April 15 so be sure to be ready to cover your sunflowers in the event of one of those late frosts.

USDA Zone Info for Flossmoor

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-15°F
Highest Expected Low-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Flossmoor

You may be interested in your other planting guides for Flossmoor.